<!DOCTYPE html>
<html lang="en" id="h1">

<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
  <style>
    /* 1 + 1 = 2 */
    div p {
      color: red;
      font-size: 40px;
    }

    /* 10 + 1 = 11 */
    .box p {
      color: green;
    }

    /* 10 + 100 = 110 */
    .box #p1 {
      color: blue;
    }

    #box #p1 {
      color: brown;
    }

    #h1 #b1 #box #p1 {
      color: aquamarine;
    }

    /* .box,
    div p,
    .p1 {} */

    .p1 {
      color: greenyellow !important;
    }

    .p1 {
      color: chocolate !important;
    }
  </style>
</head>

<body id="b1">
  <div class="box" id="box">this is tag div
    <p class="p1" id="p1" style="color: yellow;">this is tag p</p>
  </div>

</body>

</html>